A. Field of the Invention
This invention relates to the field of computer systems and more particularly to the shutdown and reset of embedded systems.
B. Description of Related Art and Advantages of the Invention
Embedded computer systems typically operate in real-time or multi-tasking environments for specific applications. Such systems typically include a processor, RAM, ROM and an interface to hardware devices required by the application. A disk drive is not normally needed because the processor in embedded systems does not normally perform general purpose file-based applications. When embedded systems are shutdown, the status of the machine may be saved by storing certain variables in non-volatile RAM, or the status may be gracefully set to a power down state from which the system may be gracefully powered-up.
Real-time or multi-tasking operating systems are available with the capability of performing in a general purpose computing environment. However, the startup, shutdown and reset of such systems is typically performed from a terminal through user action from a keyboard or a mouse. A shutdown or reset that resembles a power off condition, for example, from a reset switch, may not be performed in such general purpose environments without corrupting system files. The shutdown from a reset switch does not provide the operating system with the opportunity to perform disk synchronization or to close and save temporary files that may be open.
Embedded systems having a general purpose computing environment are finding increasing use and expanding features. For example, communications access devices are typically embedded systems. Whereas communication access devices have been designed to perform a limited role in terms of call processing and routing, with the ultimate destination for the calls being one or more host computers on the local area network, communications servers provide the network access functions of an integrated communications router in addition to a general purpose computing platform. The platform runs a commercially available stand alone or shareware operating system such as Windows.RTM. NT from Microsoft Corporation. The software that runs on the computing platform may perform, for example, network management, remote access, intranet web page, and other functions.
A communication access device with the integral general purpose computing platform, as described herein, provides a substantial advancement in the features and capabilities of a communication access device. For example, in an embodiment in which the communication access device is connected to the network, improved remote access service may be achieved since the general purpose computing platform can route certain calls to the LAN while terminating other calls, such as those calls that require access to information that is stored locally in the memory in the general purpose computing platform. Additionally, the general purpose computing platform may provide enhanced network management service efficiently controlling the flow of calls between the access device and the network. The general purpose computing platform may also provide protocol proxy service and authentication services.
Other embedded systems may find an increase in features and advantages when combined with a general purpose computing environment. For many such embedded systems however, the need to shutdown the system from the keyboard or mouse to avoid corrupting system files may be inconvenient. For example, an embedded system may have the keyboard and mouse separated from the hardware that carries out most of the embedded system and general purpose computing functions. It would be desirable if a shutdown and reset function were available without the need to use a keyboard or mouse.
The present invention includes a push button for resetting an embedded system without the need for a keyboard or mouse. The present invention also includes a system for initiating a shutdown and reset of the system in response to predetermined shutdown/reset conditions.
These and many other features and advantages of the invention will become more apparent from the following detailed description of preferred embodiments of the invention.